Multiunit electron tube



April 26, 1949. w. w. ElTEL ET AL MUL'IIUNIT ELECTRON TUBE Filed June 9, 1947 INVEN Wf/ll'am W 5/7 BY Jack 4- ME Cu//ou g/7 ATTORNEY Patented Apr. 26, 1949 UNITED STATES ATEN OFFICE MULTIUNIT ELECTRON TUBE tion of California Application .lune 9, 1947, Serial No. 753,494

Claims.

Our invention relates to electron tubes of the power or transmitting tube type, and more particularly to improvements in multi-unit tubes of the character disclosed in our U. S. Letters Patents Nos. 2, 34,683, 2424.684, and 2,424,685.

The trend in electron tube design is toward tubes capable of operation at the higher frequencies. It is not dimcult to achieve the desired electrical properties for good operation at high frequencies with tubes of small physical size because small tubes have certain inherent advantages from the standpoint of tube structure and geometry, such as maintaining closer electrode spacings and lower inductance leads. The disadvantage of small structures for power tube uses is the limitation on power output due to lack of heat dissipation from the electrodes, particularly from the anode. In other words, large physical size is incompatible with electrical properties required for higher frequency operation, and this would appear to put a ceiling on power output for high frequency tubes.

The broad object of our invention is to provide a tube capable of large power output without sacrifice of those electrical properties required for high frequency operation.

Another important object is to provide a tube structure which simplifies the manufacture of power tubes, and which enables a variety of tubes of different power ratings to be built, all from basic tube units made alike.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of our invention. It is to be understood that we do not limit ourselves to this disclosure of species of our invention, as we may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawing:

Figure 1 is a side View, partly in section and partly in elevation, showing a tube embodying the improvements of our invention; and

Figure 2 is a top view of the same.

In terms of broad inclusion, our electron tube comprises a plurality of tube units rigidly co nected together as a single structural body, each unit comprising an individual envelope having a portion formirr an external anode, and a cooler structure carried by the anodes of the units comprising a set of fins on each of the anodes and a housing connecting the sets of fins. In our preferred tube the tube units are disposed in a circle and the housing of the cooler structure is circular and arranged coaxial with the circle of 2 tube units. The envelope of each tube unit preferably has coaxial connector members thereon to which electrodes in the envolepe are connected, and terminals are provided externally of the units connected to such members.

In greater detail and referring to the drawings, we show four triode tube units 2 preferably arranged in a circle about a vertical axis, it being understood that a greater or less number of tube units may be employed and that the individual units may be other than triodes such as diodes or tetrodes. The tube units illustrated each comprise an anode 3, filamentary cathode 4 and control grid t, these being each complete tube units independently constructed and evacuated.

Anodes 3 are of the external anode type adapted for cooling by forced air or the like, and are connected to a common cooler structure I. This cooler structure is preferably circular in shape coaxial with the circle to tube units, and functions as an electrical terminal for the anodes as well as supporting connection for tying the tube units together.

A feature of our present invention is that the cooler structure comprises a set of fins 8 connected to each of the anodes, which sets of fins are connected together by a housing made up of apertured end plates 9 and a cylindrical wall II. A center post !2 secured between the end plates by screws l3 serves to fasten the cooler structure together. These parts may conveniently be of a light weight metal such as aluminum. Fins 3 in the four sets preferably extend longitudinally and radially of the respective anodes, each set of fins being connected to a tubular core piece I 4 which in turn is secured to the anode by solder it. A sleeve H is also preferably provided about each set of fins. By this arrangement a series of annular passages containing fins are provided in the cooler structure through which air may be directed. The columns of air discharging out the bottom of the cooler structure are directed along the lower portions of the tube units and serve to ventilate these parts. For purposes of appearance and protection the cooler core I l is preferably a cup-shaped piece with a closed upper end l5.

Another feature of our present invention relates to the coaxial arrangement of electrode connectors on the individual envelopes and the electrode terminal connections thereto. As shown in Figure 1, anode 3 forms the upper portion of the envelope and comprises a metal cup with an exhaust tubulation H3 at the top and a sealing flange ill at the bottom. Metallic tubulation I8 is pinched off at tip 2| after evacuation of the envelope. Flange i9 is sealed to a cylindrically-shaped envelope section 22 of vitreous material such as glass. A grid connector ring 23 is sealed to the lower end of wall section 22, and a pair of concentric cathode connector members 26 and 2B are arranged coaxially of ring 23. By this construction the cathode connectors are disposed at the envolope end opposite the anode and the grid ring 23 lies between. The envelopev is completed by a glass section 2'! sealed between grid ring 23 and the tubular outer cathode connector 24, and by a glass ring z8zsealed between metal flanges 29 and 3! on the cathode connector members.

Internally of the envelope the cage-type control grid 6 is supported on itsconnector ring 23- by a conical bracket 32. The filamentary cathode illustrated is made of hairpins of thoriated tungsten wire secured at the lower ends to alternate tabs on' flared supports 33 and 34 connected to tubular extensions 36and 31 of the cathode connector-members 24' and 26'. These filaments are tensioned b a spring pressed sleeve38 sliding on a center rod 39 and bearing against an upper spider Mhaving radialarms engaging the bights of the filaments. This particular filament structureforms no part of our present invention, it beingunderstood that any suitable type of oath ode may be used.

Externally of the tube units the "grids are connected-together by a common terminal 42 which is preferably a metal plate or disk'having apertures for receiving the grid rings 23. Suitable fastening'means is provided between terminal disk 42. and'the grid rings. A satisfactoryv means comprises arcuate lugs 43 arranged in pairs spaced about the-periphery. of the aperture and clamped together byscrews 44. These lugs provide the necessary electrical connection and mechanical support. A pair of cathode terminal plates ordisksAfi and 4"! are likewise arranged below the grid terminal. Diskdt has apertures for receiving the outer cathode connector members 2 i, and disk has apertures for receiving the projecting inner cathode connector members 2.6 Suitable connector lugs 43 similar to those above described are used to clamp the parts together. It will be seen that the superimposed disksAZ, 4'6 and 4! function to mechanically tie the lower portions of the tube units together as wellias to provide terminals for corresponding electrodes. The units are thus rigidly connected'at' the top by the cooler structure and at the'base by the terminal disks.

The improved terminal arrangement at the base is made possible by the coaxial arrangement of the grid and'cathode connector members on the units, which coaxial alignment enables the terminal disks to be positioned with registering apertures one above the other during assembly of the tube. Thealigned connector and apertured terminaldisk arrangement also results in a very rigid interconnecting structure at the base ends of the units.

We claim:

1. A multi-unit electron tube comprising a plurality of tube units disposed in a circle rigidly connected together as a single structural body, each unit comprising an individual envelope having aportion forming an external anode, and a cooler structure carried by the anodes of the units comprising a set of radial fins on each of the anodes'extending longitudinally thereof, and acircular housing coaxial with'said'circle of units and connecting said sets of fins.

2. A mul'ti-unit electron tube comprising a plurality. of tube units rigidly connected together as a single structural body, each unit comprising an individual envelope having coaxial connector members thereon, electrodes in each unit connected to said members, and terminals externally of the units connected to said members.

3. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a singlestructural body, each unit comprising an individual envelope having an anode at one end, a cathode connector member at the otherend and an intermediate grid connector ring coaxial with said member, a cathode in each unit connected to said member, a grid ineach unitconnected to its ring, a grid terminal externally of the units connected to said rings, and a cathode terminal externally of' the units connected to said members.

4. A multi-unit electron tube comprisingaplurality of tube units rigidly'connected'together as a single structural body, each unit comprising an individual envelope having an anodeat one end, a pair of concentric cathode connector members at the other end and an intermediate grid connector ring coaxial with said members, a

cathode in each unit connected to said pair: of mem-bers, a grid in each unit connected to its ring, a gridterminal externally of the units connectedto said rings, and a pair of cathode terminalmembers externallyof the units connected to said pairs of members.

5. A multi-unit electron tubecomprising a'pluralityof tube units rigidl connected'together as a single structural body, each-unit comprisingan individual. envelope having coaxial connector members thereon, electrodes in each unit connected to said members, and spaced terminal plates extending transversely of the tube units and having aligned aperturesfor receiving the connector members.

WILLIAM W. EITEL. JACK A. McCULLOUGl-I;

REFERENCES CITED.

The following references are of record in the file of this patent:

UNITED STATES PATENT-S Number Name Date 1,716,930 Prindle June 11, 1929 2,293,497 Finch Aug. 18, 1942 2,409,667 Dailey Oct. 22, 1946 2,411,046 Liimatainen Nov. 12, 1946 2,424,684 E itel-et al Jul 29, 1947 2 ,431,273 Nergaard' Nov. 18, 1947 2,441,349 Eitel et a1. May 11, 1948 

